Landing device for aeroplanes and hydroaeroplanes.



T. s. DUNCAN.

LANDING DEVICE FOR AEROPLANES AND HYDROAEROPLANES.

-APPLICATION FILED FEB. 24.1916.

Patented July 24, 1917.,

2 sHEErsAl-:EET l. C) (D DJM,

u. l h

rnzlmnumlnx HHHHHI HI IIIIHII gL//w il IIIIHH Illllfllll T. s. DUNCAN. l LANDING DEVICE FOR AEROPLANES AND HYDROAEROPLIIIIIES.

Patented Jly 24, 1917.

2 SHEETS-SHEET 2 APPLICATION FILED FEB. 24. |916.

m om. K

Ato the landing wheel axle,

THOMAS SMTH DUNCAN, 0F CRAYFORD, ENGLAND, ASSIGNOR TO VICKERS LIMITED,

0F WESTMINSTER, ENGLAND.

y LANDING 'DEVICE FOR AEROPLANES ANDy HYDROAEROPLANES.

peclication of Letters Patent.

Maasai'. Patenten Jury sa, rait.

.Application filed February 24, 1916. Serial No. 80,138.

The air chamber may carry a displacement-- ram which is so constructed and arranged that it will guide the oil cylinder during its reciprocating movements and at the same 4time will enable liquid to pass from the oil cylinder to the air chamber 'during the contraction of the telescopic members.

The said displacement ram may be made hollow and within it may be arranged a pipe whose lower or inner end terminates near the bottom of the said ram and whose upper or outer end terminates in a chamber at the upperor outer end of the ram, this chamber communicating with the aforesaid air chamber. This arrangement insures that if any appreciable quantity 0f liquid should collect at the bottom of the ram during the contraction of the parts, this liquid will during the extension of the parts be blown out through the pipe into the air chamber by the compressed air which had been compressed in the upper or outer part of the interior of the ram during the contraction of the parts.

In order that the said invention may be clearly understoodand readily carried into effect, we will describe the same more fully with reference fto the accompanying drawings, in which Figures 1 and 2 are longitudinal sections showing a constructional form of the improved landing device in its normal or extended position and in its telescoped or contracted position respectively.

Figs. 3 and 4 are longitudinal sections in different planes but otherwise similar to Figs. l and 2 showing a modified form of the landing device.

Fig. 5 is a section taken approximately on the line 1-1 of Fig. 4.

Fig. 6 is a section taken approximately on the line 2-2 of Fig. 4, and

Fig.

To all whom t may concern.'

Be it known that T, THOMAS SMITH DUN- CAN, a lsubject of the King of Great Britain, residing at Crayford, in the county of Kent, England, have invented certain new and useful Tmprovements in or Relating to the Landing Devices for Aeroplanes and Hydroaeropla'nes, of which the following is a specification.

This invention relates to aeroplane and hydro-aeroplane landing devices of the kind in which a resilient connection is provided between the landing wheels, skids or floats and the under part of the framework of the aeroplane in order to absorb or reduce the shock when the wheels or skids strike the ground at the instant of landing, the said connection comprising two telescopic mem, bers one attached to the framework of the aeroplane or hydro-aeroplane and the other the skid or the float; the said telescopic membersinclose between them compressed air and oil or other liquid', and are normally kept in an extended or partially extended'condition by the pressure of the air but are adapted lWhen subjected to shock or other form of pressure to dissipate the energy partly by further compressing` the air and partly by causing the liquid to be, forced through a passage or passages from one part to another of the device, the said passage or passages decreasing gradually in cross sectional area the greaterV the relative movement between the members, so that a graduated retardation is produced According to the present invention the req turn of the parts to their normal position by the reaction of the compressed air is re-g tarded b a piston moving with one of the? aforesai members and working in a cylinder containing or adapted to receive some of the oil or other liquid, the piston thus acting as a buffer to bring the said members gently, to rest in their normal or extended position. This piston may be in the form of an enlargement of the upperor inner end t of the oil cylinder and may work in the; lower or inner part of the air chamber. Inorder to insure that there shall be liquid be neath this enlargement even if the oil cylinder. should perform only a relatively short stroke, the said enlargement is formed 7 is a side elevation viewed in the direction of the arrow in Fig. 5, showing part ofthe displacement ram hereinafter referred to.

The sectional view line 3, 3 of Fig. 6.

The various figures show the landing device horizontal whereas it will be understood that when in position on an aeroplane or hydro-aeroplane it will be more or less Fig. 3 is taken-on the with one or more holes leading from the invertical. The left hand end of the device terior lof the oil cylinder to the lower or is hereinafterv referred to as the lower end wouter surface of thesaid enlargement. and the right hand end as the upper end.

' placement ram B is of circular cross-section ,passes through the same loosely,

and ris tapered, its smaller end being lowerr most, so that the farther it enters the oil cylinder A, the narrower becomes the annular space through which the oil can escape from the upper end of the oil cylinder, thereby insuring a graduated retarding effect. The lower end of the air cylinder C carries an adjustable stuffing box through which the upper end of the oil cylinder A projects into the space between the air chamber C and the displacement ram yB. In order to guide and support the oil cylinder A in its up and down movements in the aforesaid space, a perforated cylinder A or other form of guide is provided. The piston D is made of slnaller diameter than the smallest internal diameter of the displacement ram B and isl formed on or carried by a rod D passing through the lower end of the said ram and connected at its lower end to the base of the oil cylinder A. For the working of the landing device, suiiicient oil is used to fill the oil cylinder A and submerge the lower end of the displacement ram B, when they parts are in their extended f position, air at a suiiieiently high pressure being contained in the air chamber `CA to support the weight of the aeroplane or hydro-aeroplane. A hole B is formed in the displacement ram B near its upperfend to ypermit the compressed air to occupy the interior of the said ram as well as the air chamber C. The-lower end of the displacement ram B isperforated, or the rod D to permit the oil to Hood the lower end 'of this ram to a sligth depth when the parts are in their extended position. lt will be understood that at the moment of striking the ground or the water, the wheels and axle, the skids or the floats as the case may be, and hence also the oil cylinder A will be forced'upward relatively to the air chamber C to an extent `depending Aupon the severity of the impact. This movement of the oil cylinder causes thek air space to decrease'and aA consequent compression of the air to take place, and the displacement-ram B simultaneously through the gradually diminishing annular v space between the latter and the ram, into the; air chamber C, this action dissipating the energy of the impact. The oil driven 'out of the oil cylinder A passes through it, so that the oil, which isv in the lower end of the displacement ram B and which normally occupies a space above the piston D, flows aroundthe `edge of the piston to the underside thereof; this oil mayI be supplemented by oil which passes through the hole or other leakage space from the oil cylindervinto the ram.k When the energy of the impact has been dissipated the parts arey returned to their normal kor extended position by the compressed air, the oil collected in the air chamber C being returned to the oil cylinder by the air pressure; during this return movement the oil in the lower end of the displacement ram B beneath the piston D prevents the said piston from striking the end of this' ram, and causes adashpot action to take place.

, In the modification shown by Figs. 3, to 7 the displacement ram B is provided with flat surfaces b, I), b (see Figs. 5, 6 and 7),

which are parallel to the axis ofthe ram ners of the square hole; it'will also be seen ies f that these gapsy will become smaller in area the fartherthe oil cylinder A enters-theair chamber C. The displacement ramB thusk serves the same purpose as the ram shown v by Figs. 1 and 2 and at the same time serves 'to support the oily cylinder A during its movement in the air chamber C thereby enabling'the aforesaid perforated guide cylinder A to be dispensed with. It will be obvious that the ram instead of being of square formation mightibe polygonal or triangular in cross-section. It willalsobe understood that other similar arrangements such as a cylindricalram formed with tapering keyways or flat surfaces might be employed to achieve the same objects.

kInstead of the said gaps or otherpassage or passages being formed between the dis-y placement ram and the air chamber they may be formed between the displacement ram and a suitably shaped lrod or extension J 'j'irojecting upwardly or inwardly from the drives the oil out of the oil cylinder A .b

f for the entry of the said rod or extension.

The lower end of the displacement ram B 1,aea,a11 1a is arranged a pipe b2 whose lfower end termi- ,I nates near the bottom of the hollow ram and whose upper end is'carried by a plate b3 `which is so situated as to form a Chamber b4 communicating by the hole B with the air chamber. As aforesaid this arrangement insures that if any appreciable quantity of' oil should collect at the bottom of the hollow ram during the telescopic action of the device this oil will, during the extension of the parts, be blown out through the pipe b2 into the air chamber C. i

The piston D is in the form of an enlargement of the upper end ofthe oilcylinder and works in the lower part of the air chamber C. This enlargement' is formed with one or more holes a3 -leading from the interior of theV oil cylinder to the lower surface of the said enlargement. Thus when the oil cylinder A commences to move upward in the air chamber yC the pressure of the air inthis chamber causes some of the oil to pass through the hole or holes d to the underside of the enlargement D so that the aforesaid buHer action will take place ony the return movement 'of the oil cylinder, the oil between the underside of the enlargement and the lower end of the air chamber C being forced through the hole or holes d into the oil cylinder during thisV return movement.

It will be observed that in each of the constructions shown the ed'ective length of the guide surfaces betweenthe oil cylinder and the part or parts that guide it becomes greater as the contracting movement increases, thereby insuring. the stability of the landing device even when subjectedto violent shocks.

One or more suitable plugs are provided for enabling the oil cylinder A and the air 4chamber C to becharged or replenished with oil and compressed air when desired.

1t is important to note that the resilient landing devices above described are characterized by a complete absence of springs and valves and provide as aforesaid a comparatively long working stroke without ybeing, of large overall dimensions. lit will be understood that one or more than Vone of the devices may be usedon an aeroplane or hydroaeroplane as desired. e ,A l

ters Patent of the United States is What l' claim and desire 'to secureby Let- 1. 1n a resilient landing device for aeroplanes and hydro-aeroplanes, the combination of two telescopic members, one constituting a liquid chamberV and the otherl com-"1 prising a chamber containing gas under pressure and also comprislng a displacement ram which is arranged to move into the liquid chamber when the members are caused to contract and by means of which the opening between itself and the liquid chamber is gradually decreased upon said contraction whereby a portion of the liquid is forced from its chamber to the gas chamber.

2. ln a resilient landing device for aerovplanes and hydro-aeroplanes, the combinawhich works in a space-supplied with liquid from the said liquid chamber.

3. In a resilient landing device for aeroplanes and hydro-aeroplanes, the combination with two telescopic members one comprising a vgas chamber and a dlsplacement ram VAand the other member constituting a liquid chamber, ofv an. enlargement on said liquid chamber constituting a piston working in the lower or inner end of the air chamber, this enlargement being formed with one or more openingss'erving to place 'the lower or outer surface of the said enlargement in communication with the liquid in the liquid chamber.

4. In a resilient landing devicev for aeroplanes and hydro-aeroplan, the combination with two telescopic members one constituting a liquid chamber and the other comprising a chamber containing a gas under pressure, and also comprising adisplaceme t ram, of means vwhereby said ram will guid the liquid chamber during its reciprocating movements and at the same time will enable liquid to pass from the liquid chamber to the air chamber during the contracthe. air chamber.

1n testimony whereof, I affix my signature.

rrnonas sin'rn Duncan.

tion of the `telescopic members to further l 

